Modified two-component gelation systems, methods of use and methods of manufacture

ABSTRACT

Compositions, methods of manufacture and methods of treatment for post-myocardial infarction are herein disclosed. In some embodiments, the composition includes at least two components. In one embodiment, a first component can include a first functionalized polymer and a substance having at least one cell adhesion site combined in a first buffer at a pH of approximately 6.5. A second component can include a second buffer in a pH of between about 7.5 and 9.0. A second functionalized polymer can be included in the first or second component. In some embodiments, the composition can include at least one cell type and/or at least one growth factor. In some embodiments, the composition(s) of the present invention can be delivered by a dual bore injection device to a treatment area, such as a post-myocardial infarct region.

CROSS-REFERENCE TO RELATED APPLICATION

The application is a divisional of co-pending U.S. patent applicationSer. No. 11/496,824, filed Jul. 31, 2006 and incorporated herein byreference.

SEQUENCE LISTING

An electronic copy of the Sequence Listing entitled “P5130D_ST25.txt” isherein incorporated by reference. This Sequence Listing consists of SEQID NOs. 1-3.

FIELD OF INVENTION

Post-myocardial infarction treatments and compositions.

BACKGROUND OF INVENTION

Ischemic heart disease typically results from an imbalance between themyocardial blood flow and the metabolic demand of the myocardium.Progressive atherosclerosis with increasing occlusion of coronaryarteries leads to a reduction in coronary blood flow, which createsischemic heart tissue. “Atherosclerosis” is a type of arteriosclerosisin which cells including smooth muscle cells and macrophages, fattysubstances, cholesterol, cellular waste product, calcium and fibrinbuild up in the inner lining of a body vessel. “Arteriosclerosis” refersto the thickening and hardening of arteries. Blood flow can be furtherdecreased by additional events such as changes in circulation that leadto hypoperfusion, vasospasm or thrombosis.

Myocardial infarction (MI) is one form of heart disease that resultsfrom the sudden lack of supply of oxygen and other nutrients. The lackof blood supply is a result of a closure of the coronary artery (or anyother artery feeding the heart) which nourishes a particular part of theheart muscle. The cause of this event is generally attributed toarteriosclerosis in coronary vessels.

Formerly, it was believed that an MI was caused from a slow progressionof closure from, for example, 95% then to 100%. However, an MI can alsobe a result of minor blockages where, for example, there is a rupture ofthe cholesterol plaque resulting in blood clotting within the artery.Thus, the flow of blood is blocked and downstream cellular damageoccurs. This damage can cause irregular rhythms that can be fatal, eventhough the remaining muscle is strong enough to pump a sufficient amountof blood. As a result of this insult to the heart tissue, scar tissuetends to naturally form.

Various procedures, including mechanical and therapeutic agentapplication procedures, are known for reopening blocked arteries. Anexample of a mechanical procedure includes balloon angioplasty withstenting, while an example of a therapeutic agent application includesadministering a thrombolytic agent, such as urokinase. Such proceduresdo not, however, treat actual tissue damage to the heart. Other systemicdrugs, such as ACE-inhibitors and Beta-blockers, may be effective inreducing cardiac load post-MI, although a significant portion of thepopulation that experiences a major MI ultimately develop heart failure.

An important component in the progression to heart failure is remodelingof the heart due to mismatched mechanical forces between the infarctedregion and the healthy tissue resulting in uneven stress and straindistribution in the left ventricle. Once an MI occurs, remodeling of theheart begins. The principle components of the remodeling event includemyocyte death, edema and inflammation, followed by fibroblastinfiltration and collagen deposition, and finally scar formation fromextra-cellular matrix (ECM) deposition. The principle component of thescar is collagen which is non-contractile and causes strain on the heartwith each beat. Non-contractility causes poor pump performance as seenby low ejection fraction (EF) and akinetic or diskinetic local wallmotion. Low EF leads to high residual blood volume in the ventricle,causes additional wall stress and leads to eventual infarct expansionvia scar stretching and thinning and border-zone cell apoptosis. Inaddition, the remote-zone thickens as a result of higher stress whichimpairs systolic pumping while the infarct region experiencessignificant thinning because mature myocytes of an adult are notregenerated. Myocyte loss is a major etiologic factor of wall thinningand chamber dilation that may ultimately lead to progression of cardiacmyopathy. In other areas, remote regions experience hypertrophy(thickening) resulting in an overall enlargement of the left ventricle.This is the end result of the remodeling cascade. These changes alsocorrelate with physiological changes that result in increase in bloodpressure and worsening systolic and diastolic performance.

SUMMARY OF INVENTION

Compositions, methods of manufacture and methods of treatment forpost-myocardial infarction are herein disclosed. In some embodiments,the composition includes at least two components. In one embodiment, afirst component can include a first functionalized polymer and asubstance having at least one cell adhesion site combined in a firstbuffer at a pH of approximately 6.5. A second component can include asecond buffer in a pH of between about 7.5 and 9.0. A secondfunctionalized polymer can be included in the first or second component.In some embodiments, the composition can include at least one cell typeand/or at least one growth factor. In some embodiments, thecomposition(s) of the present invention can be delivered by a dual boreinjection device to a treatment area, such as a post-myocardial infarctregion.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1A-1B illustrate the progression of heart damage once the build-upof plaque in an artery induces an infarct to occur.

FIGS. 2A-2G show examples of chemical structures of a functionalizedpolyethylene glycol.

FIG. 3 shows a general formula for the chemical structure of afunctionalized polyethylene glycol.

FIG. 4 illustrates an embodiment of a dual bore delivery device.

FIGS. 5A-5B illustrate an alternative embodiment of a dual bore deliverydevice.

FIGS. 6A-6C illustrate a second alternative embodiment of a dual boredelivery device.

DETAILED DESCRIPTION

FIGS. 1A-1B illustrate the progression of heart damage once the build-upof plaque induces an infarct to occur. FIG. 1A illustrates a site 10where blockage and restricted blood flow can occur from, for example, athrombus or embolus. FIG. 1B illustrates resultant damage area 20 to theleft ventricle that can result from the lack of oxygen and nutrient flowcarried by the blood to the inferior region left of the heart. Damagearea 20 will likely undergo remodeling, and eventually scarring,resulting in a non-functional area.

Bioscaffoldings formed of two components and applied in situ to the leftheart ventricle can be used to treat post-myocardial infarction tissuedamage. “Bioscaffolding” and “two-component gelation system” and“gelation system” are hereinafter used interchangeably. Examples oftwo-component gelation systems include, but are not limited to, alginateconstruct systems, fibrin glues and fibrin glue-like systems,self-assembled peptides, synthetic polymer systems and combinationsthereof. Each component of the two-component gelation system may beco-injected to an infarct region by a dual-lumen delivery device.Examples of dual-lumen delivery devices include, but are not limited to,dual-needle left-ventricle injection devices, dual-needle transvascularwall injection devices and the like.

In some applications, the two-component gelation system includes fibringlue. Fibrin glue consists of two main components, fibrinogen andthrombin. Fibrinogen is a plasma glycoprotein of about 340 kiloDaltons(kDa) in its endogenous state. Fibrinogen is a symmetrical dimercomprised of six paired polypeptide chains, alpha, beta and gammachains. On the alpha and beta chains, there is a small peptide sequencecalled a fibrinopeptide which prevents fibrinogen from spontaneouslyforming polymers with itself. In some embodiments, fibrinogen ismodified with proteins. Thrombin is a coagulation protein. When combinedin equal volumes, thrombin converts the fibrinogen to fibrin byenzymatic action at a rate determined by the concentration of thrombin.The result is a biocompatible gel which gelates when combined at theinfarct region. Fibrin glue can undergo gelation between about 5 toabout 60 seconds. Examples of fibrin glue-like systems include, but arenot limited to, Tisseel™ (Baxter), Beriplast P™ (Aventis Behring),Biocol® (LFB, France), Crosseal™ (Omrix Biopharmaceuticals, Ltd.),Hemaseel HMN® (Haemacure Corp.), Bolheal (Kaketsuken Pharma, Japan) andCoStasis® (Angiotech Pharmaceuticals).

In some applications, the two-component gelation system includesself-assembled peptides. Self-assembled peptides generally includerepeat sequences of alternating hydrophobic and hydrophilic amino acidchains. The hydrophilic amino acids are generally charge-bearing and canbe anionic, cationic or both. Examples of cationic amino acids arelysine and arginine. Examples of anionic amino acids are aspartic acidand glutamic acid. Examples of hydrophobic amino acids are alanine,valine, leucine, isoleucine or phenylalanine Self-assembled peptides canrange from 8 to 40 amino acids in length and can assemble into nanoscalefibers under conditions of physiological pH and osmolarity. Insufficient concentration and over time, the fibers can assemble into aninterconnected structure that appears macroscopically as a gel.Self-assembled peptides typically undergo gelation between severalminutes to several hours. Examples of self-assembled peptides include,but are not limited to: AcN-RARADADARARADADA-CNH₂ (RAD 16-II),containing the sequence RARADADARARADADA (SEQ ID NO. 1);VKVKVKVKV-PP-TKVKVKVKV-NH₂ (MAX-1), containing the sequenceVKVKVKVKV-PP-TKVKVKVKV (SEQ ID NO. 2); and AcN-AEAEAKAKAEAEAKAK-CNH₂(EAK16-II), containing the sequence AEAEAKAKAEAEAKAK (SEQ ID NO. 3);wherein Ac indicates acetylation, R is arginine, A is alanine, D isaspartic acid, V is valine, K is lysine, P is proline and E is glutamicacid.

In some applications, the two-component gelation system is an alginateconstruct system. One component may be an alginate conjugate (oralginate alone) which can include alginate and a protein constituent.The second component may be a salt. Examples of alginate conjugates caninclude, but are not limited to, alginate-collagen, alginate-laminin,alginate-elastin, alginate-collagen-laminin and alginate-hyaluronic acidin which the collagen, laminin, elastin, collagen-laminin or hyaluronicacid is covalently bonded (or not bonded) to alginate. Examples of saltswhich can be used to gel the alginate constructs include, but are notlimited to, calcium chloride (CaCl₂), barium chloride (BaCl₂) orstrontium chloride (SrCl₂).

In one embodiment, the alginate construct is alginate-gelatin. Themolecular weight of the gelatin may be in the approximate range of 5 kDato 100 kDa. The relatively low molecular weight of gelatin offersprocessing advantages in that it is more soluble and has lower viscositythan hydrogels of higher molecular weight. Another advantage of gelatinis that it contains from 1 to 4 RGD (arginine-glycine-aspartic acidpeptide sequence) sites per molecule. RGD is a common cell adhesionligand and would increase the retention of cells within the infarct zonewhere the bioscaffolding is formed. The cells retained by the RGD sitesmay be cells co-injected with the bioscaffolding components or dispersedthroughout a component of the system.

The gelatin may be a porcine gelatin or a recombinant human gelatin. Theporcine gelatin is a hydrolyzed type 1 collagen extracted from porcineskin. In one embodiment, the molecular weight of the porcine gelatin isapproximately 20 kDa. The human gelatin is produced by bacteria usinghuman genetic material. The human recombinant gelatin is equivalent tothe porcine gelatin but may reduce the likelihood of an immune responsewhen injected into an infarct region of a human subject.

Alginate is a linear polysaccharide derived from seaweed and containsmannuronic (M) and guluronic acid (G), presented in both alternatingblocks and alternating individual residues. It is possible to use someof the carboxyl groups of the alginate as sites to graft useful celladhesion ligands, such as collagen, laminin, elastin and other peptidefragments of the ECM matrix, forming an alginate conjugate, becausealginate does not have RGD groups for cell attachment.

The alginate-gelatin conjugate can be formed of approximately 1% to 30%and more particularly approximately 10% to 20% gelatin (either porcineor human recombinant) and approximately 80% to 90% alginate. Arelatively lower proportion of gelatin is used in the conjugate toretain gelation capacity of native alginate because the carboxyl groupsof alginate that cause the gelation may be bound up in thealginate-gelatin conjugate.

In some embodiments, the two-component gelation system includespolyethylene glycols. PEG is a synthetic polymer having the repeatingstructure (OCH₂CH₂)_(n). A first component may be a polyethylene glycol(PEG) polymer functionalized with at least two nucleophilic groups.Examples of nucleophilic groups include, but are not limited to, thiol(—SH), thiol anion (—S⁻), and amine (—NH₂). A “nucleophile” is a reagentwhich is attracted to centers of positive charge. A nucleophileparticipates in a chemical reaction by donating electrons to anelectrophile in order to form a chemical bond. A second component may bea PEG polymer functionalized with at least two electrophilic groups.Examples of electrophilic groups include, but are not limited to,N-hydroxy succinimide ester (—NHS), acrylate, vinyl sulfone, andmaleimide. —NHS, or succinimidyl, is a five-member ring structurerepresented by the chemical formula —N(COCH₂)₂. An “electrophile” is areagent attracted to electrons that participates in a chemical reactionby accepting an electron pair in order to bond to a nucleophile. Thetotal number of electrophilic and nucleophilic groups should be greaterthan 4.

In some embodiments, two functionalized PEGs comprising a PEGfunctionalized with at least two nucleophilic groups and a PEGfunctionalized with at least two electrophilic groups can be combined ina 1:1 ratio. The PEGs can be stored in a 0.01M acidic solution at a pHbelow about 4.0. At room temperature and standard concentration,reaction and cross-linking between the two functionalized PEGs occursbeginning at approximately pH greater than 6.5. Under these conditions,reaction kinetics are slow. When 0.3 M basic buffer solution at pH about9.0 is added to the PEGs, gelation occurs in less than 1 minute. Thissystem exhibits poor cytocompatibility due to the low pH of thefunctionalized PEG solution and the high osmolality pH 9.0 buffer.“Cytocompatibility” refers to the ability of media to provide anenvironment conducive to cell growth. Additionally, this system does notinclude any cell adhesion sites.

Modified Polyethylene Glycol Gelation Systems

In some embodiments, a bioscaffolding is formed from combiningfunctionalized polymers (bioscaffolding precursors) with anextra-cellular matrix (ECM) protein at physiological osmolality. Theresulting bioscaffolding can be in a pH range of between about 6.5 andabout 7.5. Examples of ECM proteins include, but are not limited to,collagen, laminin, elastin and fragments thereof, in addition to,proteins, protein fragments and peptides with cell adhesion ligands suchas RGD groups. In some embodiments, cells can be added to thebioscaffolding precursors. Examples of cell types include, but are notlimited to, localized cardiac progenitor cells, mesenchymal stem cells(osteoblasts, chondrocytes and fibroblasts), bone marrow derivedmononuclear cells, adipose tissue derived stem cells, embryonic stemcells, umbilical-cord-blood-derived stem cells, smooth muscle cells orskeletal myoblasts. In some embodiments, growth factors can be added tothe system. Examples of growth factors include, but are not limited to,isoforms of vasoendothelial growth factor (VEGF), fibroblast growthfactor (FGF, e.g. beta-FGF), Del 1, hypoxia inducing factor (HIF1-alpha), monocyte chemoattractant protein (MCP-1), nicotine, plateletderived growth factor (PDGF), insulin-like growth factor 1 (IGF-1),transforming growth factor (TGF alpha), hepatocyte growth factor (HGF),estrogens, follistatin, proliferin, prostaglandin E1 and E2, tumornecrosis factor (TNF-alpha), interleukin 8 (Il-8), hematopoietic growthfactors, erythropoietin, granulocyte-colony stimulating factors (G-CSF)and platelet-derived endothelial growth factor (PD-ECGF).

The polymers can include synthetic polymers, such as polyamino acids,polysaccharides, polyalkylene oxide or polyethylene glycol (PEG). Themolecular weight of the compounds can vary depending on the desiredapplication. In most instances, the molecular weight (mol. wt.) is about100 to about 100,000 mol. wt., and more preferably about 1,000 to about20,000 mol. wt.

In some embodiments, the polymer is polyethylene glycol. As used herein,the term “polyethylene glycol(s)” includes modified and/or derivatizedpolyethylene glycols. According to some embodiments, a firstfunctionalized PEG can be functionalized by at least two reactivegroups, such as electrophilic groups. Examples of reactive groupsinclude, but are not limited to, a succinimidyl group (—NHS), a vinylgroup, such as acrylate, vinylsulfone, vinyl ether, allyl ether, vinylester, vinyl ketone or maleimide, and nitrophenolate or similar leavinggroup. According to some embodiments, a second functionalized PEG can befunctionalized by at least two reactive groups, such as nucleophilicgroups. Examples of reactive groups include, but are not limited to, athiol group, an amino group, a hydroxyl group, phospine radical (PH₂)and —CO—NH—NH₂. Representative functionalized PEGs with electrophilicgroups are shown in FIGS. 2A through 2G. A general representativeformula for functionalized PEGs with nucleophilic groups is shown inFIG. 3. In some embodiments a PEG functionalized with electrophilicgroups is combined with a PEG functionalized with nucleophilic groups toform a bioscaffolding gel. The total number of electrophilic andnucleophilic groups should be greater than 4.

The branched conformation of the PEGs represented in FIGS. 2A-2G & 3 isnot limiting. In some embodiments, the combined functionality of thePEGs can be greater than four. “Functionality” refers to the number ofelectrophilic or nucleophilic groups on the polymer core that arecapable of reacting with other nucleophilic or electrophilic groups,respectively, to form a gel. That is, as long as the PEGs to be combinedare at least difunctional, i.e., each PEG contains at least twonucleophilic or electrophilic groups, the functionalized PEGs can becombined to form a bioscaffolding gel. The total number of electrophilicand nucleophilic groups should therefore be greater than 4.

In some embodiments, a bioscaffolding can include a first component withat least one functionalized PEG and an ECM protein, and a secondcomponent of buffer. “Component” hereinafter refers to one part of atwo-part system and can include multiple constituents (e.g., a mixture).In one embodiment, the first component can include a mixture of a firstfunctionalized PEG, such as —NHS PEG (or other functionalized PEG withat least two reactive groups), a second functionalized PEG, such as —SHPEG (or other functionalized PEG with at least two reactive groups), andan ECM protein. In some embodiments, the first component can includefirst functionalized polymer only, such as —NHS PEG (or otherfunctionalized PEG with at least two reactive groups) and an ECMprotein.

In some embodiments, the first functionalized PEG can be combined withthe second functionalized PEG in a 1:1 ratio. In some embodiments, e.g.,the functionalized PEGs can be combined in a ratio less than 1:1. Forexample, the two PEGs can have different number of functional groupsand, as a result, the PEG stoichiometry could be altered. Alternatively,the crosslinking density may be altered by varying the polymer ratio. Insome embodiments, the functionalized PEGs are combined in the solidphase. When preparing to deliver to a treatment site, the mixture can besuspended in a pH 6.5 buffer at approximately physiological osmolality,i.e., 280-300 mOsm/kg H₂O. Examples of buffers include, but are notlimited to dilute hydrogen chloride and citrate buffers.

The second component can include a buffer in a pH range fromapproximately 7.5 to 9.5 at a concentration from about 140 mM to about150 mM. Examples of buffers include sodium phosphate and sodiumcarbonate buffers. The buffer can be at approximately physiologicalosmolality, i.e., 280-300 mOsm/kg H₂O. In some embodiments, the secondcomponent can include an —SH PEG and the buffer (or other functionalizedPEG with at least two reactive groups).

In some embodiments, a cell type can be added to the first component.Examples of cell types include, but are not limited to, localizedcardiac progenitor cells, mesenchymal stem cells (osteoblasts,chondrocytes and fibroblasts), bone marrow derived mononuclear cells,adipose tissue derived stem cells, embryonic stem cells,umbilical-cord-blood-derived stem cells, smooth muscle cells or skeletalmyoblasts. For example, human mesenchymal stem cells (hMSC) can be addedto the first component. In some embodiments, a growth factor can beadded to the first component. In some applications, the functionalizedPEGs can react with the growth factors which could stabilize the growthfactors, extend their half-life or provide a mode for controlled releaseof the growth factors. The growth factors can act to help survival ofinjected hMSC or endogenous progenitor cells at the infarct region. Inaddition, the growth factors can aid direct endogenous progenitor cellsto the injury site.

In general, cells do not attach to PEG surfaces or gels formed from PEGpolymers. That is, PEG polymers do not provide a cytocompatibleenvironment for cells. Collagen or gelatin or any other ECM protein suchas fibronectin, may be added to improve cytocompatibility. However, inthe case of collagen, for example, the collagen added to the mixture ofPEGs can make the mixture very viscous and therefore not conducive withcatheter delivery systems. It is anticipated that the pH of the firstcomponent and the concentration of the second component, as described inembodiments of the invention, will increase the cytocompatibility of thecell types even with an ECM protein present.

In some embodiments, the first component can be combined with the secondcomponent to produce a bioscaffolding at an infarct region. Whencombined, the resulting bioscaffolding gel can be at a pH of between 6.8and 7.4. Although the low buffer concentration of the second componentmay slow the reaction down, the resulting gel can enable improvedcytocompatibility. The ECM protein can provide cell adhesion cites toenable cell spreading and migration. “Cell spreading” refers to thenaturally occurring morphology that some cells attain when they areallowed to grow on cytocompatible surfaces. In the case of hMSC, thenatural morphology is a flattened, spindle-shaped morphology. In someembodiments, the N-terminus and lysine and arginine side groups of theECM may react with the —NHS PEG. This may provide better mechanicalstability of the gel and reduce the tendency of the gel to swell. Thisreaction is what forms the gel.

In some embodiments, the —NHS group of the —NHS PEG can be replaced witha vinyl constituent such as acrylate, vinylsulfone, vinyl ketone, allylester, allyl ketone or maleimide group(s). When mixed with an —SH PEG atappropriate conditions, these groups can react with the thiol group(s)of the —SH PEG through a Michael type reaction. Michael type reactionsare well known by those skilled in the art. In some embodiments, thereaction could be activated with a buffer in a pH range of between about6.0 and about 9.0, by a catalytic amount of various amines or acombination thereof. It is anticipated that a Michael type reactionwould contribute to the long term stability of the resulting gel sincethioether bonds are formed as compared to the more hydrolytically labilethioester bonds formed from the reaction of thiols with activatedesters. In some embodiments, the —NHS group of the —NHS PEG can bereplaced with a leaving group such as a nitrophenolate.

In some embodiments, the —SH group of the —SH PEG can be replaced withan amino group to form an amide bond when combined with an —NHS oralternatively functionalized PEG.

Methods of Treatment

Devices which can be used to deliver each component of the gel include,but are not limited to, dual-needle left-ventricle injection devices,dual-needle transvascular wall injection and dual syringes. Methods ofaccess to use the minimally invasive (i.e., percutaneous or endoscopic)injection devices include access via the femoral artery or thesub-xiphoid. “Xiphoid” or “xiphoid process” is a pointed cartilageattached to the lower end of the breastbone or sternum, the smallest andlowest division of the sternum. Both methods are known by those skilledin the art.

FIG. 4 illustrates an embodiment of a dual syringe device which can beused to deliver the compositions of the present invention. Dual syringe400 can include first barrel 410 and second barrel 420 adjacent to oneanother and connected at a proximal end 455, distal end 460 and middleregion 465 by plates 440, 445 and 450, respectively. In someembodiments, barrels 410 and 420 can be connected by less than threeplates. Each barrel 410 and 420 includes plunger 415 and plunger 425,respectively. Barrels 410 and 420 can terminate at a distal end intoneedles 430 and 435, respectively, for extruding a substance. In someembodiments, barrels 410 and 420 can terminate into cannula protrusionsfor extruding a substance. Barrels 410 and 420 should be in close enoughproximity to each other such that the substances in each respectivebarrel are capable of mixing with one another to form a bioscaffoldingin the treatment area, e.g., a post-infarct myocardial region. Dualsyringe 400 can be constructed of any metal or plastic which isminimally reactive or completely unreactive with the formulationsdescribed in the present invention. In some embodiments, dual syringe400 includes a pre-mixing chamber attached to distal end 465.

In some applications, first barrel 410 can include a first component ofa two-component polyethylene glycol gelation system and second barrel420 can include a second component of the system according to any of theembodiments described previously. A therapeutic amount of the resultinggel is between about 25 μL to about 200 μL, preferably about 50 μL. Dualsyringe 400 can be used during, for example, an open chest surgicalprocedure.

FIGS. 5A-5B illustrate an embodiment of a dual-needle injection devicewhich can be used to deliver the compositions of the present invention.Delivery assembly 500 includes lumen 510 which may house deliverylumens, guidewire lumens and/or other lumens. Lumen 510, in thisexample, extends between distal portion 505 and proximal end 515 ofdelivery assembly 500.

In one embodiment, delivery assembly 500 includes first needle 520movably disposed within delivery lumen 530. Delivery lumen 530 is, forexample, a polymer tubing of a suitable material (e.g., polyamides,polyolefins, polyurethanes, etc.). First needle 520 is, for example, astainless steel hypotube that extends a length of the delivery assembly.First needle 520 includes a lumen with an inside diameter of, forexample, 0.08 inches (0.20 centimeters). In one example for aretractable needle catheter, first needle 520 has a needle length on theorder of about 40 inches (about 1.6 meters) from distal portion 505 toproximal portion 515. Lumen 510 also includes auxiliary lumen 540extending, in this example, co-linearly along the length of the catheter(from a distal portion 505 to proximal portion 515). Auxiliary lumen 540is, for example, a polymer tubing of a suitable material (e.g.,polyamides, polyolefins, polyurethanes, etc.). At distal portion 505,auxiliary lumen 540 is terminated at a delivery end of second needle 550and co-linearly aligned with a delivery end of needle 520. Auxiliarylumen 540 may be terminated to a delivery end of second needle 550 witha radiation-curable adhesive, such as an ultraviolet curable adhesive.Second needle 550 is, for example, a stainless steel hypotube that isjoined co-linearly to the end of main needle 520 by, for example, solder(illustrated as joint 555). Second needle 550 has a length on the orderof about 0.08 inches (0.20 centimeters). FIG. 5B shows a cross-sectionalfront view through line A-A′ of delivery assembly 500. FIG. 5B showsmain needle 520 and second needle 550 in a co-linear alignment.

Referring to FIG. 5A, at proximal portion 515, auxiliary lumen 540 isterminated to auxiliary side arm 460. Auxiliary side arm 560 includes aportion extending co-linearly with main needle 520. Auxiliary side arm560 is, for example, a stainless steel hypotube material that may besoldered to main needle 520 (illustrated as joint 565). Auxiliary sidearm 560 has a co-linear length on the order of about, in one example,1.2 inches (3 centimeters).

The proximal end of main needle 520 includes adaptor 570 foraccommodating a substance delivery device (e.g., a component of atwo-component bioerodable gel material). Adaptor 570 is, for example, amolded female luer housing. Similarly, a proximal end of auxiliary sidearm 560 includes adaptor 580 to accommodate a substance delivery device(e.g., a female luer housing).

The design configuration described above with respect to FIGS. 5A-5B issuitable for introducing two-component gel compositions of the presentinvention. For example, a gel may be formed by a combination (mixing,contact, etc.) of a first component and a second component.Representatively, a first component may be introduced by a one cubiccentimeter syringe at adaptor 570 through main needle 520. At the sametime or shortly before or after, second component including a silkprotein and optionally a least one cell type may be introduced with aone cubic centimeter syringe at adaptor 580. When the first and secondcomponents combine at the exit of delivery assembly 500 (at an infarctregion), the materials combine (mix, contact) to form a bioerodable gel.

FIGS. 6A-6C illustrate an alternative embodiment of a dual-needleinjection device which can be used to deliver two-component gelcompositions of the present invention. In general, the catheter assembly600 provides a system for delivering substances, such as two-componentgel compositions, to or through a desired area of a blood vessel (aphysiological lumen) or tissue in order to treat a myocardial infarctregion. The catheter assembly 600 is similar to the catheter assembly600 described in commonly-owned, U.S. Pat. No. 6,554,801, titled“Directional Needle Injection Drug Delivery Device”, which isincorporated herein by reference.

In one embodiment, catheter assembly 600 is defined by elongatedcatheter body 650 having proximal portion 620 and distal portion 610.Guidewire cannula 670 is formed within catheter body (from proximalportion 610 to distal portion 620) for allowing catheter assembly 600 tobe fed and maneuvered over guidewire 680. Balloon 630 is incorporated atdistal portion 610 of catheter assembly 600 and is in fluidcommunication with inflation cannula 660 of catheter assembly 600.

Balloon 630 can be formed from balloon wall or membrane 635 which isselectively inflatable to dilate from a collapsed configuration to adesired and controlled expanded configuration. Balloon 630 can beselectively dilated (inflated) by supplying a fluid into inflationcannula 660 at a predetermined rate of pressure through inflation port665 (located at proximal end 620). Balloon wall 635 is selectivelydeflatable, after inflation, to return to the collapsed configuration ora deflated profile. Balloon 630 may be dilated (inflated) by theintroduction of a liquid into inflation cannula 660. Liquids containingtreatment and/or diagnostic agents may also be used to inflate balloon630. In one embodiment, balloon 630 may be made of a material that ispermeable to such treatment and/or diagnostic liquids. To inflateballoon 630, the fluid can be supplied into inflation cannula 660 at apredetermined pressure, for example, between about one and 20atmospheres. The specific pressure depends on various factors, such asthe thickness of balloon wall 635, the material from which balloon wall635 is made, the type of substance employed and the flow-rate that isdesired.

Catheter assembly 600 also includes at least two substance deliveryassemblies 605 a and 605 b (not shown; see FIGS. 6B-6C) for injecting asubstance into a myocardial infarct region. In one embodiment, substancedelivery assembly 605 a includes needle 615 a movably disposed withinhollow delivery lumen 625 a. Delivery assembly 605 b includes needle 615b movably disposed within hollow delivery lumen 625 b (not shown; seeFIGS. 6B-6C). Delivery lumen 625 a and delivery lumen 625 b each extendbetween distal portion 610 and proximal portion 620. Delivery lumen 625a and delivery lumen 625 b can be made from any suitable material, suchas polymers and copolymers of polyamides, polyolefins, polyurethanes andthe like. Access to the proximal end of delivery lumen 625 a or deliverylumen 625 b for insertion of needle 615 a or 615 b, respectively isprovided through hub 635 (located at proximal end 620). Delivery lumens625 a and 625 b may be used to deliver first and second components of atwo-component gel composition to a post-myocardial infarct region.

FIG. 6B shows a cross-section of catheter assembly 600 through line A-A′of FIG. 6A (at distal portion 610). FIG. 6C shows a cross-section ofcatheter assembly 600 through line B-B′ of FIG. 6A. In some embodiments,delivery assemblies 605 a and 605 b are adjacent to each other. Theproximity of delivery assemblies 605 a and 605 b allows each componentof the two-component gelation system to rapidly gel when delivered to atreatment site, such as a post-myocardial infarct region.

From the foregoing detailed description, it will be evident that thereare a number of changes, adaptations and modifications of the presentinvention which come within the province of those skilled in the part.The scope of the invention includes any combination of the elements fromthe different species and embodiments disclosed herein, as well assubassemblies, assemblies and methods thereof. However, it is intendedthat all such variations not departing from the spirit of the inventionbe considered as within the scope thereof.

What is claimed is:
 1. A kit comprising: a first syringe containing amixture of a first functionalized polyethylene glycol polymer and anextracellular matrix protein having at least one cell-adhesion site in afirst buffer at physiological osmolality; a second syringe containing asecond buffer at a concentration from 140 millimolar to 150 millimolarand a physiological osmolality; and a dual bore catheter configured toaccept the first syringe and the second syringe through respective boresand configured for delivery of the mixture and the second buffer to apost-myocardial infarct region, wherein the physiological osmolality isin a range from 280 mOsm/kg H₂O to 300 mOsm/kg H₂O, and wherein theextracellular matrix protein is selected from the group consisting ofgelatin, laminin, elastin, and an arginine-glycine-aspartic acid peptidesequence.
 2. The kit of claim 1, further comprising a secondfunctionalized polymer, wherein the second functionalized polymer isdisposed within one of the first syringe or the second syringe.
 3. Thekit of claim 1, wherein the first functionalized polymer is one of anactivated ester-terminated polyethylene glycol or a vinyl-terminatedpolyethylene glycol.
 4. The kit of claim 2, wherein the secondfunctionalized polymer is one of a thiol-terminated polyethylene glycolor an amino-terminated polyethylene glycol.
 5. The kit of claim 2,wherein the mixture has a pH of less than 6.5.
 6. The kit of claim 1,wherein the second buffer has a pH in a range from 7.5 to 9.0.
 7. Thekit of claim 1, wherein the first mixture further comprises one of acell, a growth factor or a combination thereof.
 8. The kit of claim 7,wherein the cell, the growth factor, or the combination thereof iscombined with the first mixture.
 9. The kit of claim 7, wherein thegrowth factor is selected from the group consisting of vasoendothelialgrowth factor (VEGF), fibroblast growth factor (FGF), Del 1, hypoxiainducing factor (HIF), monocyte chemoattractant protein (MCP), nicotine,platelet derived growth factor (PDGF), insulin-like growth factor 1(IGF-1), transforming growth factor (TGF), hepatocyte growth factor(HGF), estrogens, follistatin, proliferin, prostaglandin E1 (PGE1) andE2 (PGE2), tumor necrosis factor (TNF), interleukin 8 (IL-8),hematopoietic growth factors, erythropoietin (EPO), granulocyte-colonystimulating factors (G-CSF) and platelet-derived endothelial growthfactor (PD-ECGF).
 10. The kit of claim 7, wherein the cell is selectedfrom the group consisting of localized cardiac progenitor cells,mesenchymal stem cells, bone marrow derived mononuclear cells, adiposetissue derived stem cells, embryonic stem cells,umbilical-cord-blood-derived stem cells, smooth muscle cells andskeletal myoblasts.
 11. The kit of claim 2, wherein the firstfunctionalized polymer and the second functionalized polymercollectively have a functionality greater than four.
 12. The kit ofclaim 2, wherein the contents of the first syringe and the contents ofthe second syringe comprise a gel at pH 7.2 when combined.